Method and system for tracking lubricant leakage from downhole drilling equipment

ABSTRACT

A method of detecting leakage from a drilling tool comprising putting at least one transmitter ( 110 ) in lubricant within the tool ( 26 ) and scanning for the transmitter ( 120 ) with a receiver ( 120 ) at the surface or in a downhole measurement and communications system ( 25 ). If the transmitter ( 110 ) is detected, then one can deduce that the lubricant has leaked from the tool ( 26 ). The method therefore provides an early warning of potential or impending tool failure.

CROSS REFERENCE TO RELATED APPLICATIONS

None.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The inventions disclosed and taught herein relate generally to drilling techniques; and more specifically related to detecting a leak in a drilling assembly.

2. Description of the Related Art

U.S. Patent Application No. 20070008115 teaches “a system and method for monitoring, detecting, tracking and identifying explosive materials. The system and method involves placing RFID tags within or on explosive materials.”

U.S. Patent Application No. 20080058680 teaches “a sensor for measuring bladder volume that includes an RFID chip (particularly, a passive RFID chip) to generate driving power using an electric wave generated by a reader, and to transmit information on the measured bladder volume to the reader using an elastic wave or an electromagnetic wave, and to a system and method of managing a bladder using the same. A sensor for measuring bladder volume according to an embodiment of the invention includes an antenna that receives an electric wave, a transducer generates a predetermined wave and measures the bladder volume indicating the size of a bladder using the predetermined wave, and an RFID chip that generates and supplies power using the electric wave received by the antenna, generates information on the bladder volume from the measured bladder volume, and transmits the generated information to the outside through the antenna. The sensor for measuring bladder volume is attached to the skin in an abdominal region of a user. According to the embodiment of the invention, since the sensor for measuring bladder volume does not use a battery, it is reduced in size, thereby improving mobility. Therefore, an adverse affect when the sensor is inserted into the body through a surgical operation can be prevented.”

Japanese Patent Application No. JP 2006337098 teaches a “system for measuring flow velocity in tubing for resolving the above problem is provided with RFID chips 20 mixed in fluid flowing inside the piping 60, a plurality of readers 30 (30 a, 30 b) arranged along the piping 60 with a predetermined interval and reading the signal output from the RFID chips 20 mixed in the fluid 70 flowing inside the piping 60, and a computer 40 calculating the flow velocity of the fluid 70 flowing inside the piping 60 from the information correlated with the individual information of the reader 30 having read, with the time when the reader 30 read the signal output from the RFID chips 20 and the distance of a plurality of the readers 30 which read the signals.”

Japanese Patent Application No. JP 2007163255 teaches “[a] tag 2 operated in some frequency in LF band, MF band, HF band and VHF band (for example, 13.56 MHz band) is installed on a place where a water leak often occurs such as a periphery of a joint of a distributing water pipe, and existence of a water leak is determined based on a change of the communication state between the tag 2 and a reader/writer 7. The tag 2 operated in a short wave band such as the HF band or the VHF band is more inexpensive than a tag operated in another frequency, and a versatile reader/writer 7 can be utilized, and a tag antenna has a structure wherein a lead wire is wound and the antenna shape can be changed freely in accordance with a domain where the water leak is detected. Consequently, the water leak can be detected simply, surely and inexpensively.”

PCT Patent Application No. WO 2008028746 teaches “[a] method of and apparatus for monitoring flow velocity in a fluid flow system, the method comprising the steps of injecting multiple RFID-tags at an injecting location, measuring final presence data of the RFID-tags at a final measuring location downstream of said injecting location by a RFID-transceiver, and calculating a flow velocity by using the measured final presence data. The flow system may be a pipeline system and it may comprise a tank, whereby measuring locations may be on the enclosure of, or within, the tank, to enable calculation of the flow velocity profile in the tank. The method and apparatus are especially suitable for monitoring flow velocity of medium consistency process fluid of chemical or mechanical wood processing industry.”

U.S. Pat. No. 7,066,280 “[a]n improved drill bit for use in drilling operations in a wellbore comprising a bit body including a plurality of bit legs, each supporting a rolling cone cutter, a lubrication system for a rolling cone cutter, at least one lubrication sensor for monitoring at least one condition of said lubricant during drilling operations, and an electronics member in the bit body for recording data obtained form said lubrication sensor.”

The inventions disclosed and taught herein are directed to an improved method and system for detecting leaking in drilling equipment.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, the present invention includes a method of detecting leakage from a drilling tool comprising suspending at least one transmitter in lubricant within the tool and scanning for the transmitter at the surface. If the transmitter is detected, then one can deduce that the lubricant has leaked from the tool. The method therefore provides an early warning of impending tool failure.

In another embodiment, the present invention includes a method of detecting leakage from a drilling tool assembly comprising suspending a plurality of transmitters in lubricant within different sections of the assembly and scanning for the transmitters at the surface. If transmitters are detected, then one can deduce not only that the assembly is leaking but also which section is leaking. The method therefore provides an early warning of impending tool failure. Furthermore, if the same section routinely experiences such leakage, the assembly and/or operation thereof can be redesigned.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 depicts drilling operations conducted utilizing a downhole drill bit having lubrication systems in accordance with the present invention;

FIG. 2 is a perspective view of a downhole drill bit;

FIG. 3 is a longitudinal sectional view of a portion of the downhole drill bit depicted in FIG. 2; and

FIG. 4 is a flow chart of a method of detecting leaks from the downhole drill bit.

DETAILED DESCRIPTION

The Figures described above and the written description of specific structures and functions below are not presented to limit the scope of what Applicants have invented or the scope of the appended claims. Rather, the Figures and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present inventions will require numerous implementation-specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system-related, business-related, government-related and other constraints, which may vary by specific implementation, location and from time to time. While a developer's efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of skill this art having benefit of this disclosure. It must be understood that the inventions disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. Lastly, the use of a singular term, such as, but not limited to, “a,” is not intended as limiting of the number of items. Also, the use of relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like are used in the written description for clarity in specific reference to the Figures and are not intended to limit the scope of the invention or the appended claims.

Particular embodiments of the invention may be described below with reference to block diagrams and/or operational illustrations of methods. It will be understood that each block of the block diagrams and/or operational illustrations, and combinations of blocks in the block diagrams and/or operational illustrations, can be implemented by analog and/or digital hardware, and/or computer program instructions. Such computer program instructions may be provided to a processor of a general-purpose computer, special purpose computer, ASIC, and/or other programmable data processing system. The executed instructions may create structures and functions for implementing the actions specified in the block diagrams and/or operational illustrations. In some alternate implementations, the functions/actions/structures noted in the figures may occur out of the order noted in the block diagrams and/or operational illustrations. For example, two operations shown as occurring in succession, in fact, may be executed substantially concurrently or the operations may be executed in the reverse order, depending upon the functionality/acts/structure involved.

Applicants have created a method of detecting leakage from a drilling tool comprising putting at least one transmitter in lubricant within the tool and scanning for the transmitter at the surface. If the transmitter is detected, then one can deduce that the lubricant has leaked from the tool. The method therefore provides an early warning of impending tool failure.

FIG. 1 depicts one example of drilling operations conducted in accordance with the present invention with an improved downhole drill bit, such as that described in U.S. Pat. No. 7,066,280 incorporated herein by specific reference. As is shown, a conventional rig 3 includes a derrick 5, a derrick floor 7, a draw works 9, a hook 11, a swivel 13, a kelly joint 15, and a rotary table 17. A drillstring 19 which includes a drill pipe 21 and a drill collar 23 extends downward from the rig 3 into a borehole 1. The drill collar 23 preferably includes a number of tubular drill collar members which connect together, including a measurement-while-drilling logging subassembly and cooperating mud pulse telemetry data transmission subassembly, which may comprise a measurement and communication system 25.

During drilling operations, drilling fluid, or mud, is circulated from a mud pit 27 through a mud pump 29, through a desurger 31, and through a mud supply line 33 into the swivel 13. The drilling mud flows through the kelly joint 15 and into an axial central bore in the drillstring 19. Eventually, it exits through jets or nozzles which are located in a downhole drill bit 26 which is connected to the lowermost portion of the measurement and communication system 25. The drilling mud flows back up through the annular space between an outer surface of the drillstring 19 and an inner surface of the wellbore 1, to be circulated to the surface where it is returned to the mud pit 27 through a mud return line 35. A shaker screen may be used to separate formation cuttings from the drilling mud before it returns to the mud pit 27.

The measurement and communication system 25 may utilize a mud pulse telemetry technique to communicate data from a downhole location to the surface while drilling operations take place. To receive data at the surface, a transducer 37 is provided in communication with the mud supply line 33. This transducer generates electrical signals in response to drilling mud pressure variations. These electrical signals are transmitted by a surface conductor 39 to a surface electronic processing system 41, which is preferably a data processing system with a central processing unit for executing program instructions, and for responding to user commands entered through either a keyboard or a graphical pointing device.

FIG. 2 is a perspective view of an improved downhole drill bit 26 in accordance with the present invention. The downhole drill bit 26 includes an externally-threaded upper end 53 which is adapted for coupling with an internally-threaded box end of the lowermost portion of the drillstring 19. In alternative embodiments, any conventional or novel coupling may be utilized.

Additionally, the bit 26 includes a bit body 55. A nozzle 57 and the other obscured nozzles jet fluid that is pumped downward through the drillstring 19 to cool the downhole drill bit 26, clean the cutting teeth of the downhole drill bit 26, and transport the cuttings up the annulus. The downhole drill bit 26 preferably includes three bit heads (but may alternatively include a lesser or greater number of heads) which extend downward from the bit body 55 and terminate at bearings (not depicted in FIG. 2 but depicted in FIG. 3), such as journal bearings or roller bearings, which receive rolling cone cutters 63,65,67. Each of the rolling cone cutters 63,65,67 is lubricated by a lubrication system which is accessed through compensator caps 59,61. Each of the rolling cone cutters 63,65,67 includes cutting elements, such as cutting elements 71,73, and optionally include gage trimmer inserts, such as gage trimmer insert 75. As is conventional, the cutting elements 71,73 may comprise tungsten carbide inserts which are press fit into holes provided in the rolling cone cutters 63,65,67. Alternatively, the cutting elements 71,73 may be machined from the steel which forms the body of the rolling cone cutters 63,65,67. The gage trimmer inserts, such as gage trimmer insert 75, are press fit into holes provided in the rolling cone cutters 63,65,67. No particular type, construction, or placement of the cutting elements is required for the present invention, and the drill bit 26 depicted in FIGS. 2 and 3 is merely illustrative of one widely available downhole drill bit.

FIG. 3 is a longitudinal section view of the downhole drill bit 26 of FIG. 2. One bit head 81 is depicted in this view. However, as discussed above, the bit 26 may include one, two, three, or more bit heads. In a preferred embodiment, the bit 26 includes three bit heads.

A central bore 83 is defined interiorly of the bit heads 81. For each bit head, a lubrication system 85 includes a compensator 87 which includes a compensator diaphragm 89 and lubrication passages, or reservoirs, 91,93,95. The lubrication passages 91,93,95 are utilized to direct lubricant from the compensator 87 to an interface between the rolling cone cutter 63 and a cantilevered journal bearing 97, to lubricate the mechanical interface 99 thereof. The rolling cone cutter 63 is secured in position relative to the cantilevered journal bearing 97 by a ball lock 101 which is moved into position through the lubrication passage 93 through an opening which is filled by a plug weld 103. The interface 99 between the cantilevered journal bearing 97 and the rolling cone cutter 63 is sealed by an o-ring seal 105; alternatively, a rigid or mechanical face seal may be provided in lieu of an o-ring seal. The lubricant which is routed from the compensator 87 through the lubrication passages 91,93,95 lubricates the interface 99 to facilitate the rotation of the rolling cone cutter 63 relative to the cantilevered journal bearing 97. The compensator 87 may be accessed from the exterior of the downhole drill bit 26 through the removable compensator cap 61.

One will appreciate that if the lubricant leaks from the lubrication passages 91,93,95, excessive wear of the rolling cutter cone 63, the journal bearing 97, or both will result. Such excessive wear can cause premature failure of the drill bit 26. Therefore, it is advantageous to detect any lubricant leakage. In one embodiment of the present invention, referring also the FIG. 4, transmitters 110 are suspended in the lubricant in the lubrication passages 91,93,95, as shown in step A. Thus, if lubricant leaks from the lubrication passages 91,93,95, the lubricant will carry one or more of the transmitters 110 with it. Any leaking lubricant will mingle with the drilling fluid, or mud, and be carried to the surface along with the formation cuttings, as described above. As the mud carries the leaking lubricant to the surface, the mud will also carry any of the transmitters 110 that have leaked from the drill bit 26 with the leaking lubricant.

One should appreciate that the transmitters 110 need to be very small to ensure they leak out with any leaking lubricant. Additionally, the transmitters 110 need to be small in order to avoid any abrasive action they may have on the rolling cutter cone 63 and/or the journal bearing 97. Therefore, in a preferred embodiment, the transmitters 110 are nano-sized devices.

A receiver 120 is preferably placed at the surface to scan for the transmitters 110, as shown in step B. If the receiver 120 detects one or more of the transmitters 110, the receiver 120 can signal or initiate an alert that the drill bit 26 is leaking lubricant, as shown in step C. The receiver 120 may be placed along the mud return line 35 and/or in the vicinity of the mud pit 27. The receiver 120 may be a stand alone device operable to generation signals and alerts. Alternatively, the receiver 120 may be coupled with the surface electronic processing system 41, or some other computer or signal processing system, which in turn provides operating signaling and/or alerting. The processing system 41 may also log such signals and alerts for future reference, diagnosis, and/or redesign as may be necessary.

In one embodiment of the present invention, the transmitters 110 are radio frequency identification devices RFID and the receiver 120 is a RFID reader. The reader 120 preferably substantially continuously transmits an interrogation signal toward the mud return line 35 and/or the mud pit 27. If any of the RFID transponders 110 receive the interrogation signal, they respond with a response signal. Upon receipt of a response signal, the reader 120 signals or initiates a signal that the drill bit is leaking lubricant.

In one embodiment, as discussed above, the drill bit 26 includes three rolling cone cutters 63,65,67, each with their own lubrication systems including the lubrication passages 91,93,95. The RFID transponders 110 may be coded with unique response signal codes for each of the rolling cone cutters 63,65,67 or even each transmitter 110. Therefore, by reading the code of the received response signal, the receiver 120 and/or the processing system 41 may determine which of the rolling cone cutters 63,65,67 is leaking, as shown in step D.

By detecting the presence of one or more transponders 110 at the surface, using the reader 120, the present invention can detect when the bit 26 is leaking. Furthermore, using unique coding within the response signals, the present invention can determine which portion, section, or cone of the bit 26 is leaking. Additionally, by monitoring frequency of detection and/or quantity of transponders 110 detected, over time, the present invention can determine how badly, the bit 26 is leaking. All of this information is especially helpful in warning or alerting an operator of premature, potential, and/or impending bit failure. Finally, by tracking how often a particular portion, section, or cone of the bit 26 leaks, the present invention can be used to redesign the bit 26 and/or the process in which it is used.

It should be appreciated that the borehole 1 is expected to be thousands of feet deep. It should also be appreciated that the transmitters 110 and receiver 120 have limited effective ranges, typically on the order of a few feet for RFID technology, although some systems may offer effective ranges as great as three hundred feet. For one embodiment of the present invention, the effective range is preferably between approximately three inches and approximately five feet. In the preferred embodiment, partially because the transmitters 110 are preferably as small as possible, the effective range is less than one foot, and as low as approximately three inches.

Thus, until the drill bit 26 begins to leak lubricant, the reader 120 is not expected to detect the transponders 110. In other words, because the drill bit 26 containing the transponders 110 is normally operated well beyond the effective range with respect to the reader 120, when the reader 120 detects one or more of the transponders 110 in the drilling mud, one can deduce that the drill bit 26 is leaking lubricant. When the drill bit 26 loses lubricant, one can appreciate that the increased friction leads to excessive wear and therefore impending drill bit 26 failure. The reader 120 itself, or the processing system 41, may therefore provide early warning of impending drill bit 26 failure upon detection of one or more transponders 110.

In an alternative embodiment, rather than locating the reader 120 at the surface, the reader 120 may be located in the drillstring 19. With the reader 120 located at the surface of the borehole 1, it may take anywhere between approximately thirty minutes and approximately one hundred twenty minutes for the transmitters 110 to be detected, at the surface, after leaking from the drill bit 26, at the bottom of the borehole 1. By moving the reader 120 closer to the drill bit 26, leaks may be detected much sooner, on the order of a minute or two. For example, the reader 120 may be located within the measurement and communication system 25. Portions of the measurement and communication system 25 are often located anywhere from approximately ten feet to approximately one hundred feet behind the drill bit 26. With the reader 120 located closer to the drill bit 26, but still beyond the effective range, the system of the present invention can provide much earlier leak detection.

Further, the various methods and embodiments of the present invention can be included in combination with each other to produce variations of the disclosed methods and embodiments. Discussion of singular elements can include plural elements and vice-versa. For example, the reader 120 may be located both within the drillstring 19 and at the surface.

Other and further embodiments utilizing one or more aspects of the inventions described above can be devised without departing from the spirit of the present invention. For example, the transmitters 110 may be active, stand-alone transmitters that do not wait for the interrogation signal. Rather, the transmitters 110 may substantially continuously transmit a signal indicative of their presence.

The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and/or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions.

The inventions have been described in the context of preferred and other embodiments and not every embodiment of the invention has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the invention conceived of by the Applicants, but rather, in conformity with the patent laws, Applicants intend to fully protect all such modifications and improvements that come within the scope or range of equivalent of the following claims. 

1. A method of detecting leakage from a drilling tool comprising the steps of: providing, within a reservoir of an assembly, at least one liquid; providing, within the reservoir, at least a first device operable to transmit a signal, the first device having a transmission range beyond which the signal is normally undetectable; and providing a second device operable to receive the signal, and thereby detect the presence of the first device, wherein the second device is provided beyond the transmission range with respect to the reservoir during operation of the assembly.
 2. The method as set forth in claim 1, wherein the liquid is a lubricant operable to protect the assembly from premature failure.
 3. The method as set forth in claim 1, wherein the first device is a transponder that replies to an interrogation from the second device.
 4. The method as set forth in claim 1, wherein the first device is a radio frequency identification device (RFID) and the second device is a RFID reader.
 5. The method as set forth in claim 1, wherein the assembly is a drill bit and the second device is located near an opening of a hole drilled by the drill bit.
 6. The method as set forth in claim 1, wherein, during normal operation, the reservoir is located more than one thousand feet away from the second device.
 7. The method as set forth in claim 1, wherein, upon detection of the presence of the first device, the second device initiates a warning of an impending failure of the assembly.
 8. The method as set forth in claim 1, wherein, during normal operation, at least a portion of the assembly is in contact with a fluid, different from the liquid, and the second device is positioned to scan the fluid after the fluid exits a hole drilled by the assembly.
 9. A method of detecting leakage from a drilling tool comprising the steps of: providing an assembly with at least a first reservoir and a second reservoir; providing, within the first reservoir, at least a first liquid; providing, within the first reservoir, at least a first device operable to transmit a first signal, the first device having a first transmission range beyond which the first signal is normally undetectable; providing, within the second reservoir, at least a second liquid; providing, within the second reservoir, at least a second device operable to transmit a second signal, the second device having a second transmission range beyond which the second signal is normally undetectable; and providing a third device operable to receive both the first signal and the second signal, wherein the third device is provided beyond the transmission ranges with respect to the reservoirs during operation of the assembly.
 10. The method as set forth in claim 9, wherein the liquids are lubricants operable to protect the assembly from premature failure.
 11. The method as set forth in claim 9, wherein the first and second devices are transponders that reply to an interrogation from the second device.
 12. The method as set forth in claim 9, wherein the first and second devices are radio frequency identification devices (RFID) and the third device is a RFID reader.
 13. The method as set forth in claim 9, wherein the assembly is a drill bit and the third device is located near an opening of a hole drilled by the drill bit.
 14. The method as set forth in claim 9, wherein, during normal operation, the reservoirs are located more than one thousand feet away from the third device.
 15. The method as set forth in claim 9, wherein, upon detection of the presence of the first device, the second device, or both, the third device initiates a warning of an impending failure of the assembly.
 16. The method as set forth in claim 9, wherein, during normal operation, at least a portion of the assembly is in contact with a fluid, different from the liquids, and the third device is positioned to scan the fluid after the fluid exits a hole drilled by the assembly.
 17. The method as set forth in claim 9, wherein the third device is operable to distinguish between the first and second signals, and thereby initiate an indication of which reservoir is leaking.
 18. A method of detecting leakage from a drilling tool comprising the steps of: drilling a hole with a drilling assembly, the assembly including at least a first reservoir and a second reservoir therein; transporting cuttings from the hole with a drilling fluid; providing, within the first reservoir, at least a first lubricant; providing, within the first reservoir, a first plurality of radio frequency identification devices operable to respond to an interrogation signal with a first response signal identifying the first reservoir; providing, within the second reservoir, at least a second lubricant; providing, within the second reservoir, a second plurality of radio frequency identification devices operable to respond to the interrogation signal with a second response signal identifying the second reservoir; scanning the fluid after the fluid has left the hole with a radio frequency reader operable to initiate the interrogation signal and receive the response signals; and indicating, upon reception at least one of the response signals, which reservoir is leaking based upon the received response signal. 